In order to log a user in via SSO, you need to have all of this information available to you. Then, you will generate a JWT token with username and sso_key inside the payload, encoded using your API token.

It's that simple. You then take the $jwt variable and pop it into a URL: https://your-domain.voiceportals.net/sso/your-user-id/jwt-token
So, say your user id is 238, your domain is awesomevoip and your token is the one generated above, the URL would look like: